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Mgcarpathian: Mapgen loop optimisations. fabs() -> std::fabs()

* Mgcarpathian: ZYX -> ZXY mapgen loop optimisation.

* 'pow(n, 3)' to 'n * n * n' type optimisations.

* fabs() -> std::fabs().
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paramat committed Mar 29, 2018
1 parent 8f827ee commit 2c490dddc037d7d1cf211bbf28309e31b0abdadd
Showing with 80 additions and 72 deletions.
  1. +80 −72 src/mapgen/mapgen_carpathian.cpp
@@ -192,7 +192,7 @@ void MapgenCarpathianParams::writeParams(Settings *settings) const
}


///////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////


// Lerp function
@@ -212,7 +212,7 @@ float MapgenCarpathian::getSteps(float noise)
}


///////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////


void MapgenCarpathian::makeChunk(BlockMakeData *data)
@@ -298,7 +298,7 @@ void MapgenCarpathian::makeChunk(BlockMakeData *data)
}


///////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////


int MapgenCarpathian::getSpawnLevelAtPoint(v2s16 p)
@@ -338,14 +338,15 @@ float MapgenCarpathian::terrainLevelAtPoint(s16 x, s16 z)
float hill2 = getLerp(height3, height4, mnt_var);
float hill3 = getLerp(height3, height2, mnt_var);
float hill4 = getLerp(height1, height4, mnt_var);
float hilliness = std::fmax(std::fmin(hill1, hill2), std::fmin(hill3, hill4));
float hilliness =
std::fmax(std::fmin(hill1, hill2), std::fmin(hill3, hill4));

// Rolling hills
float hill_mnt = hilliness * pow(n_hills, 2.f);
float hills = pow(hter, 3.f) * hill_mnt;

// Ridged mountains
float ridge_mnt = hilliness * (1.f - fabs(n_ridge_mnt));
float ridge_mnt = hilliness * (1.f - std::fabs(n_ridge_mnt));
float ridged_mountains = pow(rter, 3.f) * ridge_mnt;

// Step (terraced) mountains
@@ -364,7 +365,7 @@ float MapgenCarpathian::terrainLevelAtPoint(s16 x, s16 z)
}


///////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////


int MapgenCarpathian::generateTerrain()
@@ -373,10 +374,6 @@ int MapgenCarpathian::generateTerrain()
MapNode mn_stone(c_stone);
MapNode mn_water(c_water_source);

s16 stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
u32 index2d = 0;
u32 index3d = 0;

// Calculate noise for terrain generation
noise_base->perlinMap2D(node_min.X, node_min.Z);
noise_height1->perlinMap2D(node_min.X, node_min.Z);
@@ -392,70 +389,81 @@ int MapgenCarpathian::generateTerrain()
noise_mnt_var->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);

//// Place nodes
for (s16 z = node_min.Z; z <= node_max.Z; z++) {
for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
u32 vi = vm->m_area.index(node_min.X, y, z);
for (s16 x = node_min.X; x <= node_max.X;
x++, vi++, index2d++, index3d++) {
if (vm->m_data[vi].getContent() != CONTENT_IGNORE)
continue;

// Base terrain
float ground = noise_base->result[index2d];

// Gradient & shallow seabed
s32 grad = (y < water_level) ? grad_wl + (water_level - y) * 3 : 1 - y;

// Hill/Mountain height (hilliness)
float height1 = noise_height1->result[index2d];
float height2 = noise_height2->result[index2d];
float height3 = noise_height3->result[index2d];
float height4 = noise_height4->result[index2d];
float mnt_var = noise_mnt_var->result[index3d];
// Combine height noises and apply 3D variation
float hill1 = getLerp(height1, height2, mnt_var);
float hill2 = getLerp(height3, height4, mnt_var);
float hill3 = getLerp(height3, height2, mnt_var);
float hill4 = getLerp(height1, height4, mnt_var);
// 'hilliness' determines whether hills/mountains are
// small or large
float hilliness = std::fmax(std::fmin(hill1, hill2), std::fmin(hill3, hill4));

// Rolling hills
float hter = noise_hills_terrain->result[index2d];
float n_hills = noise_hills->result[index2d];
float hill_mnt = hilliness * pow(n_hills, 2.f);
float hills = pow(fabs(hter), 3.f) * hill_mnt;

// Ridged mountains
float rter = noise_ridge_terrain->result[index2d];
float n_ridge_mnt = noise_ridge_mnt->result[index2d];
float ridge_mnt = hilliness * (1.f - fabs(n_ridge_mnt));
float ridged_mountains = pow(fabs(rter), 3.f) * ridge_mnt;

// Step (terraced) mountains
float ster = noise_step_terrain->result[index2d];
float n_step_mnt = noise_step_mnt->result[index2d];
float step_mnt = hilliness * getSteps(n_step_mnt);
float step_mountains = pow(fabs(ster), 3.f) * step_mnt;

// Final terrain level
float mountains = hills + ridged_mountains + step_mountains;
float surface_level = ground + mountains + grad;

if (y < surface_level) {
vm->m_data[vi] = mn_stone; // Stone
if (y > stone_surface_max_y)
stone_surface_max_y = y;
} else if (y <= water_level) {
vm->m_data[vi] = mn_water; // Sea water
} else {
vm->m_data[vi] = mn_air; // Air
}
const v3s16 &em = vm->m_area.getExtent();
s16 stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
u32 index2d = 0;

for (s16 z = node_min.Z; z <= node_max.Z; z++)
for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
// Base terrain
float ground = noise_base->result[index2d];

// Hill/Mountain height (hilliness)
float height1 = noise_height1->result[index2d];
float height2 = noise_height2->result[index2d];
float height3 = noise_height3->result[index2d];
float height4 = noise_height4->result[index2d];

// Rolling hills
float hterabs = std::fabs(noise_hills_terrain->result[index2d]);
float n_hills = noise_hills->result[index2d];
float hill_mnt = hterabs * hterabs * hterabs * n_hills * n_hills;

// Ridged mountains
float rterabs = std::fabs(noise_ridge_terrain->result[index2d]);
float n_ridge_mnt = noise_ridge_mnt->result[index2d];
float ridge_mnt = rterabs * rterabs * rterabs *
(1.f - std::fabs(n_ridge_mnt));

// Step (terraced) mountains
float sterabs = std::fabs(noise_step_terrain->result[index2d]);
float n_step_mnt = noise_step_mnt->result[index2d];
float step_mnt = sterabs * sterabs * sterabs * getSteps(n_step_mnt);

// Initialise 3D noise index and voxelmanip index to column base
u32 index3d = (z - node_min.Z) * zstride_1u1d + (x - node_min.X);
u32 vi = vm->m_area.index(x, node_min.Y - 1, z);

for (s16 y = node_min.Y - 1; y <= node_max.Y + 1;
y++,
index3d += ystride,
VoxelArea::add_y(em, vi, 1)) {
if (vm->m_data[vi].getContent() != CONTENT_IGNORE)
continue;

// Combine height noises and apply 3D variation
float mnt_var = noise_mnt_var->result[index3d];
float hill1 = getLerp(height1, height2, mnt_var);
float hill2 = getLerp(height3, height4, mnt_var);
float hill3 = getLerp(height3, height2, mnt_var);
float hill4 = getLerp(height1, height4, mnt_var);

// 'hilliness' determines whether hills/mountains are
// small or large
float hilliness =
std::fmax(std::fmin(hill1, hill2), std::fmin(hill3, hill4));
float hills = hill_mnt * hilliness;
float ridged_mountains = ridge_mnt * hilliness;
float step_mountains = step_mnt * hilliness;

// Gradient & shallow seabed
s32 grad = (y < water_level) ? grad_wl + (water_level - y) * 3 :
1 - y;

// Final terrain level
float mountains = hills + ridged_mountains + step_mountains;
float surface_level = ground + mountains + grad;

if (y < surface_level) {
vm->m_data[vi] = mn_stone; // Stone
if (y > stone_surface_max_y)
stone_surface_max_y = y;
} else if (y <= water_level) {
vm->m_data[vi] = mn_water; // Sea water
} else {
vm->m_data[vi] = mn_air; // Air
}
index2d -= ystride;
}
index2d += ystride;
}

return stone_surface_max_y;

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